1. Field of the Invention
The present invention relates to a film holder for holding a film and an image reading apparatus for reading an image on the film held by the film holder.
2. Description of Related Art
When an image on a film is to be read by a conventional film scanner, the film is held in a film holder, and the film holder is inserted into the scanner, thereby reading the image on the film. In many cases, positive films are held in the slide mounts as shown in FIG. 20. Such a film is therefore directly inserted into a film scanner. For this film scanner, high image quality, high resolution, and the like are required as the performance specifications of the product. For this reason, to meet the image input precision (movement precision) requirement and the like, a film holder carriage held by two guide shafts is slid thereon to read an image.
FIG. 20 shows a positive mount film 100 and the internal holding structure of a film scanner. When the positive mount film 100 is held in the scanner, the film is held/fixed on a carriage 101 between holder press members 102a and 102b. The driving force from a driving unit 105 is transmitted through driving force transmission units 104a and 104b to move the carriage 101 in a direction parallel to guide shafts 103 so as to move the film illuminated by a light source relative to a one-dimensional CCD line sensor. With this operation, a two-dimensional image is read.
The conventional film scanner uses a vibrator such as a motor. A high-strength, high-rigidity housing for the motor is formed by bending metal plates or by casting and secondary machining. This housing is used to hold the motor for driving the carriage on which the film holder for holding a film is mounted.
A conventional electronic device (e.g., a film scanner) having a SCSI (Small Computer System Interface) (I/F) generally has at least two SCSI connector terminals to allow connection to another SCSI I/F-equipped device through a SCSI cable.
FIG. 31 shows such a SCSI connector and the fitting portion of a SCSI cable connected thereto. Referring to FIG. 31, reference numeral 301 denotes a SCSI connector which is fitted to a fitting portion 302 of a SCSI cable to allow input and output of image signals and the like; and 29, a printed board. In this case, the surface of the printed board 29 on which the SCSI connector 301 is mounted is defined as an surface A, and the surface opposite to the surface A is defined as a surface B. Reference numeral 304 denotes an electronic part which is the tallest part on the surface B of the printed board 29.
Referring to FIG. 31, reference symbol H1 denotes the maximum height of the SCSI connector 301; H2, the maximum height of the fitting portion 302 of the SCSI cable; H3, the maximum height of the electronic part 304; S1, the jutted size of the fitting portion 302 with respect to the SCSI connector 301 when they are fitted to each other; and t1, the thickness of the printed board 29.
When a plurality of SCSI connectors are to be mounted on such a conventional SCSI I/F-equipped device, the connectors are arranged side by side on one surface of a printed board placed in the device due to mounting limitations. This structure will be described below.
FIG. 32 shows an example of how two SCSI connectors 300 and 301 are arranged, on the surface A of the printed board 29, side by side in the direction of width. Letting W1 be the outside width of each SCSI connector, a width w of the area occupied by the two SCSI connectors is given by: EQU w=W1+W1 (1)
That is, an area having a size at least twice the width W1 of one SCSI connector is required.
FIG. 33 shows an example of the two SCSI connectors 300 and 301 that are stacked on the surface A of the printed board 29 in the direction of height. In this case, a width w2 of the area occupied by the two connectors is given by EQU w2=W1 (2)
That is, the width w2 corresponds to the width of one SCSI connector. From equations (1) and (2), we have EQU w&gt;w2 (3)
Obviously, the layout constituted by the two connectors stacked on each other in the direction of height in FIG. 33 is more compact in the direction of width than that in FIG. 32.
In general, a 135-type negative strip film is cut in units of six frames. When six-frame images are to be continuously read with the scanner, each frame to be read must be positioned with respect to the film holder for each read operation. It therefore takes much time and labor to read the images. According to some improved scanners, three frames are continuously read first, and then the film holder is rotated through 180.degree. to read the three remaining frames. This scheme, however, requires a cumbersome operation of reversing the film holder halfway in image reading.
If the film to be read is curled, it is difficult to hold the film on the film holder. In addition, the film may be soiled. If the film is held in a wrong direction, a vertically or horizontally reversed image is read. The film must therefore be set again. Once the film is held on the holder, a positional offset cannot be corrected without contaminating the film with fingerprints or the like. Furthermore, after the film holder is attached to the film scanner, the user cannot check the position of a frame before prescanning. Since high-precision parts are required for a scanner to read an image with high quality, the cost and the number of steps inevitably increase.
If a power supply circuit for supply power to the overall device and an image processing circuit for processing a read image signal are arranged nearby, the noise generated by the power supply circuit adversely affects the image processing circuit, resulting in poor image quality. In some devices, a power switch is directly mounted on a power supply board to be located on the rear side of the device body so as to ensure high resistance to noise. In this case, however, when the operator is to turn on the power supply of the device body, he/she must fumble for the power switch on the rear side of the device body or must look therein, resulting in poor operability.
Since the heat generated by the power supply circuit may adversely affect the image processing circuit, the two circuits are formed on different boards, and the power supply board and the image processing board are arranged parallel to be spaced apart from each other. Alternatively, the structural members are formed by die casting or a cooling fan is used. The addition of such parts, however, leads to an increase in cost. In addition, since the film tends to curl or discolor with an increase in temperature, the space in which the film is inserted is spaced apart from the heating members such as the power supply to ensure the movement area for the film and reduce the influence of heat, and to prevent the film from being damaged when the film holder comes into contact with the board. This structure, however, poses a problem in realizing a compact device.
The following drawbacks are posed in the conventional scanner.
When metal plate members having undergone a bending process are to be used, the degree of freedom in shape is low. In this case, since a housing must be formed by combining a plurality of members, it is difficult to attain high precision. In addition, since the housing has many flat portions, the precision may deteriorate due to the warpage of members. When a housing is to be formed by die casting and secondary machining, a high process cost is required, resulting in an increase in the cost of each member.
It is an object of the present invention to provide an apparatus which can satisfy both the precision and strength requirements for the housing. It is also an object of the present invention to reduce the vibration and noise generated by the motor.
The following problems are posed in the conventional SCSI I/F-equipped device.
If a plurality of SCSI connectors are arranged, side by side in the direction of width, on the same mounting surface of the printed board, as shown in FIG. 32, since a large space is required in the direction of width of the printed board, the overall apparatus size increases in the direction of width, although the height hi can be suppressed.
If the SCSI connectors are stacked on the mounting surface of the printed board in the direction of height, as shown in FIG. 33, a sufficient space for storing the SCSI connectors 300 and 301, the printed board 29, and the electronic part 304 is required in the direction of height, although the width of the printed board can be decreased. In the structure having the SCSI connectors stacked on each other, SCSI cables may be fitted to the SCSI connectors 300 and 301 at once in actual operation of the device. In this case, in consideration of the size S1 of each overhang of the fitting portion 302, the distance between the two SCSI connectors must be set to be at least twice the size S1 of the SCSI cable. That is, as shown in FIG. 33, the height h2 given by the following equation is required: EQU h2=H1.times.2+S1.times.2+t1+H3 (4)